Machine for grinding and pulverizing friable substances



MERE 25', 1924: ggyqwg J. P. VAN @ELDER ummm@- vFOR GRINDING 'Ama PULVE'RIZING FMABLE sUBsTAncEs Filed Aug. 22 192s ,im/mib# Johannes'Pieer l Geder fffamey' JOHANNES PIETER VANGELDER, CF GBANVLLE, NEAR SYDNEY, NEW' SOUTH THALES, AUSTRALIM MACHINE FOR GRINDING AND PULVER-IZING FRIABLE SUBSTANCES.

Application :Filed August 22, 1923.

To a?? whom. t may concern.'

Be it lrnown that i, J'orrennns PIETER VAN GnLDnn, subject ot the King of Great Britain, residing` at 200 llilliam Street, Granville. near Sydney.y New `South lVales, Australia,I have invented new and'useful mprovements in Machines ttor Grinding and Pulverizing Friable Substances, ot which the following as a speciiication.

ln the disintegrator type of crushing mill in which lumps ot triable material are smashed and pulverized by the action of revolving beaters, the granular particles which are too large to pass through the screen in the bottom oit the machine casing are retained in the casing, but on account ot their small dimensions the beaters act ine'ectively on them so that the rate'of their reduction is slow and the capacityv ot the machine is accordingly limited. This class of machine can therefore be utilized with satisfactory economy only with a comparatively coarse screen, in which condition a product having a wide range of gauge is obtained. Vhenthe product is required in a finely pulverized condition, subsequent grinding in rolls or other mills is necessary to complete the reduction.

The object of the present invention is to provide means whereby7 a complete reduction of the product to line gauge is attainable in a mill ot the revolving beater type, and an output obtained which is not less than the output of mixed gauge product which is obtainable from such mills constructed according to present practice. This object is accomplished by introducing a pair of rolls into the upper part of the beater casing so that the granular particles which are whirled by the beater action are caught in the nip of the rolls and such particles reduced by the roll action and are so brought to gauge appropriate to allow them to pass through the delivery screen. The casing is thus rapidly cleared of the coarse and intermediate granular material, so that the operation oi the beaters is not clogged and they are freed to operate eiiiciently.

The accompanying drawing is a transverse sectional elevation through a grinder constructed according to the present invention.

The beater shaft 1 is mounted for rotation at a tast speed, usually about 2,000 revolutions per minute,- in bearings (not shown).

Serial No. 658,751.

Upon this shaft an assembly of beater blades 2 of hard metal is mounted in symmetrical order with spacings of greater or less width between the neighbouring beater blades. The lowerpart of the casing in which the beaters operate is a semi-cylindrical grating or screen 3 the perforations in which are appropriate to the size of the product required to be obtained, The milled product whichl passes through these pertorations is collected in a boot or box 4, below which a conveyor belt may be arranged.

The upper part 5 of the machine casing is lined with replaceable anvil blocks 6 of hard metal, usually having corrugated taces 7. 8 is the feed throat to which the lumps of material to be comminuted are delivered from a hopper or belt or otherwise. In the lower part of the neck a replaceable plate of hard metal 9, similar to the plates 6, is disposed. 10 is an access door at one end of the easing.

The upper part of the casing is extended to form a chamber in which two grinder rolls 11 and 12 are rotatably mounted. The spindles carrying these rolls extend through the casing endg and are supported in appropriate bearings. The rolls may be of equal diameter or of differential diameters, and they may be driven at equal peripheral speeds or at differential peripheral speeds. For a machine proportioned as shown in the drawings. with the beaters arranged to revolve at 2,000 revolutions per minute the roll 12 may be driven at 400 to 500 revolu.

tions per minute and the roll 11 at any speed from 400 to 800 revolutions por minute or thereabouts.

The bearings carrying the Spindle 13 of the roll 12 are contained in slides 14, and pressure is maintained at the roller contacting faces by means ot' a bearing spring 15 the tension ot which is adjustable by means ot collar nuts 16 working on a screwed thrust spindle 17. Said spring or springs 15 take an abutment bearing against the yoke 18. 19 are collar nuts adjustable onthe spindle 17 for setting back the roll faces to any desired clearance. 20 is a hand lever acting on the back end of the spindle 17 through eccentric trunnions 21, this hand lever serving for rapidly retiring the roll 12 from the roll 11 it at any time it is found necessary to clear the rolls to remove an obstruction, 23 is a scraper plate 

